media: dvb: fix DVB_MMAP symbol name

CONFIG_DVB_MMAP was misspelled either as CONFIG_DVB_MMSP
or DVB_MMAP, so it had no effect at all. This fixes that,
to make it possible to build it again.

Fixes: 4021053ed52d ("media: dvb-core: make DVB mmap API optional")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/include/media/dvb_vb2.h b/include/media/dvb_vb2.h
index 01d1202..056adc86 100644
--- a/include/media/dvb_vb2.h
+++ b/include/media/dvb_vb2.h
@@ -103,7 +103,7 @@ struct dvb_vb2_ctx {
 	char	name[DVB_VB2_NAME_MAX + 1];
 };
 
-#ifndef DVB_MMAP
+#ifndef CONFIG_DVB_MMAP
 static inline int dvb_vb2_init(struct dvb_vb2_ctx *ctx,
 			       const char *name, int non_blocking)
 {